Who is the 49ers free safety of the future?

The 49ers signed free safety Craig Dahl yesterday, but he’s not the Niners’ free safety of the future. He may not be their free safety of the present, either. He’s probably a backup, and a mentor for whichever free safety the 49ers draft in a few weeks.

Will the Niners draft a safety who is similar to Dashon Goldson – tall and hard-hitting, like LSU’s Eric Reid – or will the Niners draft a different type of free safety? Will they look for a faster guy who can play single-high and occasionally cover slot receivers man-to-man?

If the Niners are looking for the second type, a ball hawk, an obvious fit would be Fresno State free safety, Phillip Thomas. He led the NCAA with eight interceptions last year. But he ran a 4.65 40-yard dash at the Scouting Combine. He may not be fast enough to play single-high coverage.

There aren’t a lot of fast safeties in this draft. If the 49ers want one, they may have to draft a cornerback and move him to free safety. Here are two cornerbacks who could make the position switch:

David Amerson. 6-1, 205 pounds. Ran an unofficial 4.38 40-yard dash at the Combine. Intercepted 13 passes in 2011 and 5 in 2012.

Dwayne Gratz. 5-11, 201 pounds. Ran an unofficial 4.35 40-yard dash at the Combine. Intercepted eight passes in four seasons at the University of Connecticut.

There is also Chris Culliver, who’s already a 49er, played free safety in college and ran a 4.36 40-yard dash at the 2011 Combine.